1. Field of the Invention
The present invention relates to an exposure apparatus having a plurality of stations and a plurality of substrate stages.
2. Description of the Related Art
Exposure apparatuses used for the semiconductor manufacture are required to improve both the measurement accuracy and the throughput. However, conventional exposure apparatuses sequentially execute the measurement and the exposure on one substrate stage. For this reason, these apparatuses consume much time to execute accurate measurement, resulting in a decrease in throughput.
Under the circumstances, an exposure apparatus such as a twin-stage exposure apparatus which has a plurality of substrate stages has been developed. Such an exposure apparatus can, e.g., accurately execute a measurement process on one substrate stage, parallel to an exposure process on the other substrate stage. This makes it possible to simultaneously improve both the measurement accuracy and the throughput.
Such a twin-stage exposure apparatus is disclosed in Japanese Patent Laid-Open No. 2006-269669.
However, since an exposure apparatus having a plurality of substrate stages has processing units that are separately located in a plurality of stations, the substrate stages must be swapped between the plurality of stations. As the substrate stages are frequently swapped, the throughput of the entire apparatus lowers.